Aluminum Roofing

Q.How common is aluminum
standing-seam roofing? It seems that this profile would
be better suited for heat-related expansion and
contraction than corrugated aluminum panels fastened
through their face, but my local suppliers carry only
steel standing seam.

A.Todd Miller, president of
Classic Metal Roofing Systems in Piqua, Ohio,
responds: Aluminum is a perfectly viable
material for standing seam, though probably 85
percent of metal standing-seam roofing is produced
from either galvanized steel (which has a
protective metallic coating that is primarily zinc)
or galvalume (which has a protective coating that
is primarily aluminum). Aluminum and copper each
make up about 5 percent of the market, with other
types of metals — zinc, stainless, terne
— accounting for the remaining 5
percent.

One advantage of aluminum is its permanent rust
resistance. Even though aluminum roofing always has
a prepainted finish, less care is required during
installation to protect cut edges or prevent minor
scratches than with steel roofing, most of which is
also prepainted (though galvalume is sometimes
supplied with a clear-coat finish). Also, because
aluminum roofing loses heat more rapidly than steel
roofing, it can be a more energy-efficient choice
in warm climates.

For a given thickness, aluminum standing-seam
roofing doesn't have as much structural rigidity as
steel roofing — which is often installed
over purlins — but there are aluminum
standing-seam panels that are strong enough to be
installed without decking. Typical thickness for
aluminum standing seam ranges from .032 inch to
.050 inch, with the heavier products being the ones
that can be installed over purlins rather than
decking. By comparison, steel standing-seam roofing
typically ranges from .015 inch to .030 inch
thick.

You should expect to pay about 10 percent to 20
percent more for aluminum standing-seam roofing
than for galvanized steel and galvalume
standing-seam roofing panels (which are generally
similar in price). Companies that offer aluminum
standing seam include ATAS International
(800/468-1441, www.atas.com); Classic Metal
Roofing Systems (800/543-8938,
www.classicroof.com), and
Petersen Aluminum (800/722-2523,
www.pacclad.com).